Đề 12 – Bài tập, đề thi trắc nghiệm online Hóa sinh lipid

1. Which hormone primarily stimulates lipolysis (breakdown of triglycerides) in adipose tissue?

A. Insulin

B. Glucagon

C. Growth hormone

D. Cortisol

2. Which lipoprotein is considered `good cholesterol` and helps to remove cholesterol from peripheral tissues and transport it back to the liver?

A. LDL (Low-Density Lipoprotein)

B. VLDL (Very-Low-Density Lipoprotein)

C. Chylomicrons

D. HDL (High-Density Lipoprotein)

3. Consider a scenario where an individual consumes a very high-fat meal. Which of the following metabolic responses is LEAST likely to occur shortly after this meal?

A. Increased secretion of cholecystokinin (CCK)

B. Increased activity of pancreatic lipase

C. Increased rate of fatty acid synthesis in the liver

D. Increased levels of chylomicrons in the lymph

4. Ceramides are important signaling molecules and precursors to other sphingolipids. What is ceramide composed of?

A. Sphingosine and a phosphate group

B. Sphingosine and a fatty acid

C. Glycerol and two fatty acids

D. Glycerol and a phosphate group

5. Phospholipids are amphipathic molecules, meaning they have both hydrophilic and hydrophobic regions. Which part of a phospholipid is hydrophobic?

A. Phosphate group

B. Glycerol backbone

C. Fatty acid tails

D. Choline group

6. Sphingolipids are a class of lipids found in cell membranes, particularly abundant in nerve tissue. What is the backbone structure of sphingolipids, different from glycerol in glycerophospholipids?

A. Glycerol

B. Sphingosine

C. Cholesterol

D. Ceramide

7. What is the primary storage form of lipids in animals?

A. Glycogen

B. Triglycerides

C. Phospholipids

D. Steroids

8. Which of the following lipoproteins is primarily responsible for transporting cholesterol from the liver to peripheral tissues, often associated with `bad cholesterol`?

A. HDL (High-Density Lipoprotein)

B. LDL (Low-Density Lipoprotein)

C. VLDL (Very-Low-Density Lipoprotein)

D. Chylomicrons

9. What is the function of lipid rafts in cell membranes?

A. To increase membrane fluidity uniformly

B. To create ordered microdomains enriched in cholesterol and sphingolipids, involved in signaling and membrane trafficking

C. To break down membrane lipids for recycling

D. To synthesize membrane proteins

10. What is the impact of trans fatty acids on human health?

A. They are beneficial for heart health.

B. They have no significant impact on health.

C. They increase LDL cholesterol and decrease HDL cholesterol, increasing heart disease risk.

D. They primarily affect liver function but not cardiovascular health.

11. Which type of fatty acid contains only single bonds between carbon atoms and is typically solid at room temperature?

A. Unsaturated fatty acid

B. Polyunsaturated fatty acid

C. Saturated fatty acid

D. Monounsaturated fatty acid

12. Beta-oxidation is a metabolic process that breaks down fatty acids to generate energy. Where in the cell does beta-oxidation primarily occur?

A. Cytoplasm

B. Endoplasmic reticulum

C. Mitochondria

D. Lysosomes

13. What is the role of PPARs (Peroxisome Proliferator-Activated Receptors) in lipid metabolism?

A. They are enzymes directly involved in fatty acid oxidation.

B. They are transcription factors that regulate genes involved in lipid metabolism.

C. They are transport proteins for lipids in the blood.

D. They are structural components of cell membranes.

14. What is the role of bile salts in lipid digestion?

A. To break down triglycerides into fatty acids

B. To emulsify fats, increasing the surface area for lipase action

C. To transport fatty acids into intestinal cells

D. To activate pancreatic lipase

15. What is the role of Carnitine in fatty acid metabolism?

A. To synthesize fatty acids in the cytoplasm

B. To transport fatty acids into the mitochondria for beta-oxidation

C. To break down fatty acids in the cytoplasm

D. To synthesize triglycerides in the endoplasmic reticulum

16. What is the primary function of brown adipose tissue compared to white adipose tissue?

A. Long-term energy storage as triglycerides

B. Heat generation (thermogenesis)

C. Synthesis of fatty acids

D. Storage of fat-soluble vitamins

17. What are waxes, in terms of lipid classification?

A. Triglycerides with short chain fatty acids

B. Esters of long-chain fatty acids with long-chain alcohols

C. Phospholipids with modified phosphate groups

D. Steroids with multiple hydroxyl groups

18. Lipids are a broad group of biomolecules. Which of the following is NOT a primary function of lipids in living organisms?

A. Long-term energy storage

B. Structural components of cell membranes

C. Catalysis of biochemical reactions

D. Signaling molecules (hormones)

19. Which of the following is NOT a fat-soluble vitamin?

A. Vitamin A

B. Vitamin C

C. Vitamin D

D. Vitamin K

20. Which lipid is a precursor for steroid hormones like cortisol and estrogen?

A. Triglycerides

B. Phospholipids

C. Cholesterol

D. Fatty acids

21. Which of the following is an essential fatty acid that humans must obtain from their diet?

A. Palmitic acid

B. Oleic acid

C. Linoleic acid (omega-6)

D. Stearic acid

22. Lipogenesis is the process of synthesizing new fatty acids. Which molecule is the primary precursor for fatty acid synthesis?

A. Glucose

B. Acetyl-CoA

C. Pyruvate

D. Amino acids

23. What is the role of phospholipases in lipid metabolism and signaling?

A. To synthesize phospholipids

B. To break down phospholipids, releasing fatty acids and other signaling molecules

C. To transport phospholipids across cell membranes

D. To modify cholesterol structure

24. Which enzyme is crucial for the digestion of triglycerides in the small intestine?

A. Salivary amylase

B. Pepsin

C. Pancreatic lipase

D. Nucleases

25. Eicosanoids are signaling lipids derived from fatty acids. Which fatty acid is the primary precursor for most eicosanoids, such as prostaglandins and leukotrienes?

A. Palmitic acid

B. Stearic acid

C. Arachidonic acid

D. Oleic acid

26. Which enzyme is the key regulatory enzyme in fatty acid synthesis?

A. Acetyl-CoA carboxylase

B. Fatty acid synthase

C. Carnitine acyltransferase

D. Hormone-sensitive lipase

27. Triglycerides are composed of:

A. Two fatty acids and one glycerol molecule

B. Three fatty acids and one glucose molecule

C. Three fatty acids and one glycerol molecule

D. One fatty acid and three glycerol molecules

28. Which of the following statements accurately describes the difference between omega-3 and omega-6 fatty acids?

A. Omega-3 fatty acids are saturated, while omega-6 fatty acids are unsaturated.

B. Omega-3 fatty acids have the first double bond at the 3rd carbon from the omega end, while omega-6 fatty acids have it at the 6th carbon.

C. Omega-3 fatty acids are primarily found in animal fats, while omega-6 fatty acids are mainly in plant oils.

D. Omega-3 fatty acids are essential, while omega-6 fatty acids are non-essential.

29. Zellweger syndrome is a genetic disorder affecting peroxisome biogenesis. Which lipid metabolic process would be most directly impaired in individuals with Zellweger syndrome?

A. Fatty acid synthesis in the cytoplasm

B. Beta-oxidation of very-long-chain fatty acids

C. Cholesterol synthesis in the endoplasmic reticulum

D. Triglyceride digestion in the small intestine

30. Cholesterol is a crucial lipid in animal cell membranes. What is the primary function of cholesterol in these membranes?

A. To provide energy for the cell

B. To increase membrane fluidity at low temperatures and decrease fluidity at high temperatures

C. To act as a receptor for signaling molecules

D. To transport molecules across the membrane